Cancer is one of the major causes of human morbidity and mortality. Cancer treatment is challenging because it is difficult to kill cancer cells without damaging or killing normal cells. Damaging or killing normal cells during cancer treatment causes adverse side effects in patients and can limit the amount of anticancer drug administered to a cancer patient. Certain cancer cells can differ from certain normal cells in their level of oxygenation and can be more hypoxic than normal cells. Given the importance of hypoxia in tumorigenesis and metastasis, there is a need to identify improved methods for selective treatment of subjects having a hypoxia-related disease or condition.